This invention is concerned generally with magnetic media player-recorders for example video recorders, digital audio recorders, disk drives and others, and is concerned specifically with simplified read/write scanners and scanner arrangements for such magnetic medium player-recorders. A read/write scanner is typically a cylindrical device with a portion that is movable in a rotational sense which includes a transducer or transducers that are operable for transforming a recorded signal of a magnetic medium to a physical signal, usually a magnetic field in a magnetic circuit and further to an electrical signal in a conductor, and further transmitting that electric signal to a stationary electrical amplifier circuit, and capable of the reverse operation, writing to a magnetic medium starting with an electrical signal and converting to a magnetic signal and then finally to a recording on a magnetic medium.
The manufacture of these complicated devices is quite difficult because many elements having sophisticated geometries must be precisely built and aligned. Manual labor is usually required because the arrangement of the elements including coils of complex shapes is unyielding to the properties of automation.
In state of the art equipment, one can find the most popular scanner configuration including a magnetic core with a very small gap which is generally in electro-magnetic communication with an electrical coil wound about that core. This device is sometimes called a head. The electrical coil of the head is then connected to the primary windings of a rotary transformer, the transformer being operable for passing the signal from the rotating portion of the device to a stationary amplifier circuit and having a second function in more sophisticated devices of multiplexing the signal from a plurality of heads to a single amplifier circuit. This can be accomplished if the rotary transformer has a plurality of primary windings that are arranged to communicate with a single secondary winding where each of the primary windings is in further communication with a separate head. The entire device which may be required to rotate at high speeds is required to be precisely built. The assembly process of scanners which comprises heads, transformers, and coils is time consuming and expensive. While some progress has been made in the combination of some of these parts into simpler devices, see U.S. Pat. No. 4,791,514, the devices of the art are still very cumbersome.
A further problem found in the scanners of the art, is that they are not replaceable in the location in which the are used; "field-replaceable". Because of the arrangement of the elements in these scanners, the scanner must be very precisely aligned to the motor which turns the scanner. The alignment process requires that an oscilloscope or other precision electronic measurement devices be used. It is also necessary for soldering equipment to be used in the replacement of scanners. For these reasons, it is common for head replacements to be made in an electronics shop.
This application partially relies on disclosures of a co-pending application numbered 08/076,546 and all of the disclosure made therein is hereby incorporated by reference into this application.
The inventor respectfully acknowledges the following very useful contributions to the art by the following inventors: Van Rooij in U.S. Pat. No. 4,669,022; Van Thuijl; et al, in U.S. Pat. No. 5,019,926; Zieren; et at., in U.S. Pat. No. 4,927,804, in particular FIG. 1; Lin; et al., in U.S. Pat. No. 5,072,324, in particular FIG. 4; Nakamura et al., in U.S. Pat. No. 4,402,027, in particular FIGS. 11, 15A, 15B, and 15C; Schaik in U.S. Pat. No. 5,001,585; Ota in U.S. Pat. No. 4,914,537. The very significant inventions mentioned each offer unique additions to the art which are no less than remarkable. However, these patents when considered individually or in combinations thereof, fail to provide the advantages and benefits which can be realized by applying the principles and concepts described in detail in the following text.
A scanner generally has two functions, a first is to convert magnetic signals from a magnetic media to electric signals, and a second is to multiplex magnetic signals from a plurality of transducers to a single amplifier circuit. In this sense, devices of the art are multiple transducers that are multiplexed to a single amplifier circuit through a rotary transformer or transformers. Recall that a transducer can be defined as a device that converts energy from one system to energy in another system usually of a different form. The device of the invention is distinct from the devices of the art in that a new transducer is arranged to perform the multiplexing function eliminating the need for transformers and the windings on the head's magnetic cores. The invention provides for a super single transducer that multiplexes a plurality of head elements through various magnetic paths including some stationary paths that are in communication with electronic amplifier circuits. The multiplexing and energy conversion functions are integrated together in a single transformerless transducer device. One can immediately recognize the devices of the invention because the primary and associated secondary windings of transformers are absent in the very distinct scanner arrangements provided therein.